Objective：To assess the coagulation status of patients undergoing arthroplasty after administration of rivaroxaban with thromboelastograph（TEG） in perioperative period，and to analyze the relation between coagulation status and blood platelet count. Methods：Eighty-six patients undergoing arthroplasty in our department in 2014 were included prospectively. All the patients were treated with 10 mg of rivaroxaban for 12 h after operation to prevent blood clots. TEG parameters and platelet count were analyzed simultaneously on the day before operation and on postoperative days 1，3，5 and 7. The proportion of hypercoagulability and mean platelet count were compared at different time points. And the correlation between hypercoagulable states and platelet count was per－formed with the use of correlation analysis. Results：There were significant changes in the distribution of different hypercoagulable states on days 1-3 and on days 3-7. Seven days after operation，86% patients were found with hypercoagulable state. Of these patients with hypercoagulable state，90.5% patients demonstrated platelet or mixed hypercoagulability（maximal amplitude（MA） values were greater than 70 mm）. On day 3 after operation，the average amount of platelet count decreased slightly than that before opertation（P=0.063），but it were significantly higher（P=0.000） than the preoperative level on day 7 after operation. We also found positive correla－tion between MA and platelet count during the progress. Conclusion：TEG result indicates that the proportion of patients with hyper－coagulable state can not be reduced by a short time application of rivaroxaban. The increase of platelet count after operation may play an important role in the progress of blood hypercoagulability.